Comparison of catalytic performance of different types of graphene in Li-O₂ batteries

We report comparative catalytic studies of two types of commercial graphene nanoplatelets as electrode materials with different physical properties for Li-O₂ batteries. The graphene nanoplatelets were characterized by field-emission scanning electron microscopy, transmission electron microscopy, N₂ physisorption, X-ray photoelectron spectroscopy, and Raman spectroscopy. The electrochemical performance of the graphene nanoplatelets, which have large pore volume density, large pore diameter, and high population of defect sites, was evaluated using galvanostatic discharge-charge cycling and a depth-of-discharge test. Higher specific capacity of the Li-O₂ battery was achieved when graphene nanoplatelets were used as an electrode material; this specific capacity could be associated with pore volume density, pore diameter, and number of defects in the graphene nanoplatelets.